Electrical heating unit.



F. KUHN & F. E. SHAILOR.

ELECTRICAL HEATING UNIT.

APPLICATION FILED OCT. I5. 1915.

Patented May 917.

2 SHEETS-S F. KUHN & F. E. SHAILOR.

ELECTRICAL HEATING UNIT.

APPLICATION FILED OCT. 15, 1915.

Patented May 15, 1917.

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a top plate UNITED STATES PATENT FRANK KUHN AND FRANK E. SHAILOR, OF DETROIT, MICHIGAN, ASSIGNOBS TO AMERE- CAN ELECTRICAL HEATER. COMPANY, OF DETROTLT, MICHIGAN, A. CORPORATION OF MICHIGAN.

ELECTRICAL HEATING UNIT.

Specification of Letters Patent.

Patented May 153, 191?.

To all whom it may concern:

Be it known that we, FRANK KUHN and FRAN 1; E. SIIAILOR, both citizens of the United States of America, residing at Detroit, in the county of \Vayne and State of Michigan, have invented certain new and useful Improvements in Electrical Heating Units, of which the following is a specification, reference being had therein to the accompanying drawings.

The invention relates to electrical heating units particularly designed for use in con nection with electrically heated ovens, but applicable also to other uses, and the invention comprises the novel construction as hereinafter set forth.

In the drawings:

Figure 1 is a perspective view of the unit;

Fig. 2 is a cross section thereof;

Fig. 3 is a plan; and

Fig. 4; is a section at right angles to Fig. 2.

A is an oven casing. B is our improved unit, which is arranged above the bottom of the oven and comprises a sheet metal pan or guard G spaced from the oven bottom by supporting frames D, and having at its sides and inner edges upturned flanges E, with a downturned flange F at its outer edge. G are resistor coils which are wound upon insulator supports H, preferably porcelain tubes. I is an insulator block for the terminal contacts J, which contacts project rear- Ward from the unit and are adapted to enage cooperating contacts K in an insulator block L at the rear of the oven. M are connectors between the contacts J and the resistor coils, which are preferably bent to embrace the insulator supports-H and are secured to the resistor by clamps M.

To secure the proper distribution of the heat throughout the oven and to avoid danger of overheating or scorching at the bottom the resistors G are shielded from direct radiation against the pan C. To this end the depending frame I) is provided with D, which is spaced from the pan, and is attached thereto by metal clips N, preferably spotwelded to the pan. The insulator supports H are secured at opposite ends to the frame D, and to prevent displacement of the resistor through the breaking of these tubes, a metallic strip 0 is passed. completely through each tube, the ends of this strip being secured to the end flanges D ofthe frame D. The upper part of the oven chamber is heated by the convection of the hot air coming in direct contact with the resistor and the heated parts below the pan. The air thus heated passes around the sides of the pan, and to prevent short circuiting to the center, deflector plates P are placed upon the oven sides, and are adapted to engage the upturned flanges E of the pan. Thus the hot air is compelled to travel upward between the oven sides and the deflectors P until it has reached the proper height within the oven chamber, when it passes over the tops of the deflectors and toward the center of the oven space.

To lessen the cost of manufacture the pan with the parts of the frame D, as well as the connectors M, clips N, etc, are formed of sheet metal stampings and in assembling these parts are preferably secured as 'far as possible by spot-welding. There is also preferably a central supporting post Q which is spot-welded to the bottom of the pan and supports the latter from the oven bottom. The insulator block I is secured by clips R also spot-welded to the bottom of the pan.

In use, the unit may be readily inserted or withdrawn from the oven, the flanges E engaging the deflector plates P forming guides for properly centering the pan and drawing the contacts J into engagement with the socket contacts K. When in operation, the heat generated in the resistor coils is communicated by radiation and convection to the bottom of the pan, and by convection to the space within the oven chamber, after first passing around the sides and over the deflectors P. This will secure a very uniform distribution of the heat, which may be varied as desired by proper regulation of the circuits which include the resistor coils. \Yhat we claim as our invention is: An electrical heating unit, comprising a pan, :1 depending frame secured to said pan,

an insulator rod extending across said depending frame, a resistor coiled upon said insulator rod, terminal contacts, an insulator block for supporting said contacts mounted on the bottom of said pan, connectors extending from said terminal contacts bent to embrace said insulator rod, and clamps for securing said connectors to said resistor.

In testimony whereof we afiix our signatures in presence of two Witnesses.

FRANK KUHN. FRANK E. SHAILOR. lVit-nesses CHARLES G, SPICE, OTIS C. FUNDERBURK, 

